In the oil and gas industry, operating companies which own and/or manage hydrocarbon wells evaluate the wells by wireline logging. In wireline well logging, one or more tools are connected to a power and data transmission cable or "wireline" and are lowered into the well borehole to obtain measurements of geophysical properties for the area surrounding the borehole. The wireline supports the tools as they are lowered into the borehole, supplies power to the tools and provides a communication medium to send signals to the tools and receive data from the tools. Commonly, tools are lowered to a depth of interest in the well and are then retrieved. As the tools are retrieved, they send data about the geological formations through which they pass through the wireline to data acquisition and processing equipment at the surface, usually contained inside a logging truck or a logging unit.
The data acquisition and processing equipment, including software, compiles the data from the tools into a "log," a plot which presents the geophysical information concerning the geological formations encountered by the well, frequently by depth. Logs can also be used to evaluate current production from producing wells or to inspect the integrity of production equipment in a producing well. In any case, the data gathered during the logging operation is generally presented on the log by depth, but may also be presented by time, or any other index by which multiple physical entries are recorded. U.S. Pat. No. 5,051,962 (incorporated by reference) describes such a well logging system controlled by a general purpose computer programmed for real time operation. Various data acquisition and processing software programs are known in the art. An example of data acquisition and processing software is Schlumberger's proprietary MAXIS.TM. system, which is a suite of separate computer programs.
The data acquisition and processing software writes the log data to two types of locked format files on disk. By "locked," it is meant that the format files cannot be written to and read from at the same time. The two types of locked format files are distinguished by the type of information they contain: one is a data format file and the other is a graphics format file. The data format file contains the numerical properties of the log data; the graphics format file contains the pictorial representation of the data. The data acquisition and processing software continues writing the log data to the locked data format file and the locked graphics format file until the log is complete. Then the data from the locked data format file and the locked graphics format file may be translated from digital readings into physical form by a marking device such as a printer. In addition to the locked data format file and the locked graphics format file, the data acquisition and processing software may send the log data to a viewing monitor, via a renderer. Using the monitor, the well logging professional ("logging engineer") conducting the logging operation can view the log as it is being compiled.
After the log is compiled, it can be transmitted to the operating company's headquarters for interpretation and review by management. The paper log may be sent directly from the wellsite to the operating company as a facsimile. Alternatively, the completed locked data format file can be sent from the wellsite to a data processing center via satellite using a protocol such as DECNET. The data processing center could in turn transmit the log as a facsimile to the operating company. As another alternative, the completed locked data format file can be sent from the wellsite to an operating company using a computer program such as Blast.TM. by U.S. Robotics.
The data acquired by logging is often crucial to the decision-making process on what will be done with the well being logged. Take, for example, a well which has just been drilled and logged. Depending on the results of the log, the well could be drilled deeper, plugged and abandoned as non-productive or cased and tested--or perhaps the decision will be that additional logs are required before the decision on the disposition of the well can be made. The results of the log may also help determine whether the well requires stimulation or special completion techniques, such as gas lift or sand control. In any case, these decisions are crucial and have to be made very quickly. Mistakes or even mere delay can be extremely expensive.
Because log interpretation is part art and part science, the operating company which is drilling or producing the well frequently desires to have its own personnel viewing the log data as the well is being logged. But the operating company may be located half a world away from the well itself. Drilling and production activities are often located in remote locations and it is difficult for the operating company to have its own personnel, such as a geologist or petrophycist, join the wireline company's logging engineer on site during the logging operation. Sometimes logistics or severe weather conditions prevent the operating company from sending anyone to the wellsite for the logging operation. Furthermore, sending personnel to wellsites is expensive and exposes them to all of the hazards of the drilling or production operation, as well as the hazards and inconvenience of travel. As a consequence, tentative decisions often have to be made before the operating company can complete its review of the actual logging data, relying solely on the interpretations conducted at the welisite.
Accordingly, a need exists for a system or method which would allow the operating company personnel at a location remote from the wellsite to view the log as it is compiled in at least near real time.
A further need exists for a system or a method which will allow real time communication during a logging operation between persons at a remote location viewing the logging data and the well logging engineer.
Because the data from the logging operation is of a highly competitive nature and is extremely confidential, a need exists for a system or method which will send well data from a wellsite to a remote location in near real time, in such a way that the data is not susceptible to being misdirected or lost.
A further need exists for a system or a method which will allow persons to view the logging data in near real time, without the expense of travelling to the wellsite and without being exposed to the hazards of the wellsite.